So far as I know, the Hook But the real name, I cant find anywhere.
An indentation of the shoreline is a cove or bay.
Phillips head screwdrivers only work on Phillips head screws--which are ones with an "x" indentation on the head of the screw. A straight screwdriver works on screws with a single line indentation on the head of the screw.
An indentation on the top of the head is most likely due to an injury. However, the only individual that can answer this would be a physician.
The deep indentation formed by the ilium, ischium, and pubis is called the acetabulum. The acetabulum is a cup-shaped socket where the head of the femur (thigh bone) articulates to form the hip joint.
Lumen
The indentation above the upper lip and below the nose is called the Philtrum.
This indentation is called the oral groove which leads to the gullet. See the link below for a diagram:
occipital
It's called an Indent, or Indentation.
A shoreline indentation is called a bay. It is a curved area of water partially surrounded by land, often less exposed to the open sea than a gulf.
It is "in the back of my head." You might also say "the answer is on the tip of my tongue" if you have something that you almost remember, but can't quite.
The back of the head is called the occiput. It is the anatomical term used to describe the posterior portion of the head.